The Trump administration has ordered researchers at the National Institutes of Health to stop obtaining new fetal tissue, a move that may jeopardize HIV research, according to news reports.

Science magazine reported Friday that the administration quietly ordered NIH scientists to stop acquiring new fetal tissue, which in particular affects two laboratories, the Gladstone Center for HIV Cure Research in San Francisco and Rocky Mountain Labs in Hamilton, Montana. The article quoted one scientist involved in HIV research, Gladstone Director Warner Greene, as saying he and other researchers were “devastated.” The study was “poised to go,” but the NIH’s move “knocked our collaboration off the rails,” Greene told the magazine. The experiment involved implanting the tissue in mice to study the early processes by which HIV infects cells.

In September, the administration canceled a contract with Advanced Bioscience Resources, an Alameda, California-based company that supplies fetal tissue for scientific research. In a statement, the Department of Health and Human Services said that after a review of the contract between ABR and the Food and Drug Administration, HHS “was not sufficiently assured that the contract included the appropriate protections applicable to fetal tissue research or met all other procurement requirements.”

ABR did not respond to a request for comment.

The FDA contract, worth more than $15,000, drew anger from the Susan B. Anthony List, an anti-abortion group, which sent a letter to HHS Secretary Alex Azar on Sept. 11 objecting to the contract. The letter referenced “disturbing undercover videos” obtained by the Center for Medical Progress in 2015 that allegedly showed staff from Planned Parenthood discussing the sale of organs from aborted fetuses. However, while the videos sparked controversy, it was shown that the group heavily edited them in order to mislead viewers into thinking that they showed Planned Parenthood seeking to profit from the sale of tissue.

Following the administration’s order to stop acquiring fetal tissue, the NIH said Monday it would pledge $20 million to find alternatives to the use of fetal tissue, which is implanted in mice in order to “humanize” them so that they can mimic the biological conditions of human subjects. The Science report noted that humanized mice are especially valuable in HIV research because they can be infected with the virus, which monkeys cannot, and dozens of genetically identical subjects can be used to test HIV drugs.